Affiliation: University of California
- Markov transition models for binary repeated measures with ignorable and nonignorable missing values- Xiaowei Yang
Division of Biostatistics, Department of Public Health Sciences, University of California, Davis, CA 95616, USA
Stat Methods Med Res 16:347-64. 2007..Markov transition models provide a novel reconceptualization of treatment outcomes, offering both intuitive statistical values and relevant clinical insights...
- Imputation-based strategies for clinical trial longitudinal data with nonignorable missing valuesXiaowei Yang
Division of Biostatistics, School of Medicine, University of California, Med Sci 1 C, Suite 200, Davis, CA 95616, USA
Stat Med 27:2826-49. 2008..For illustration, the strategies were applied to a data set with continuous repeated measures from a smoking cessation clinical trial...
- Functional regression analysis using an F test for longitudinal data with large numbers of repeated measuresXiaowei Yang
Department of Public Health Sciences, Division of Biostatistics, University of California, Davis, CA 95616, USA
Stat Med 26:1552-66. 2007..A simulation study is also conducted under the condition of the smoking data to investigate the statistical power for the F test, Wilks' likelihood ratio test, and the linear mixed-effects model using AIC...
- Hypothesis testing in functional linear regression models with Neyman's truncation and wavelet thresholding for longitudinal dataXiaowei Yang
Division of Biostatistics, Department of Public Health Sciences, School of Medicine, University of California, Davis, CA 95616, USA
Stat Med 27:845-63. 2008..Since a FLRM can be viewed as a natural extension of the traditional multiple linear regression model, the development of this model and computational tools should enhance the capacity of medical statistics for longitudinal data...
- A quasi F-test for functional linear models with functional covariates and its application to longitudinal dataHongquan Xu
Department of Statistics, University of California, Los Angeles, CA 90095, USA
Stat Med 30:2842-53. 2011..For illustration, we apply the proposed procedure to a longitudinal depression data set with repeatedly measured methamphetamine use as a predictor. We conduct a simulation study to assess the size and the power of the test...
- Assessing missing data assumptions in longitudinal studies: an example using a smoking cessation trialXiaowei Yang
BayesSoft Inc, 11075 Santa Monica Blud, Suite 200, Los Angeles, CA 90025, USA
Drug Alcohol Depend 77:213-25. 2005..A carbon monoxide longitudinal data set in a smoking cessation study is used for illustration...
- Imputation and variable selection in linear regression models with missing covariatesXiaowei Yang
Department of Biostatistics, University of California, 11075 Santa Monica Boulevard, Suite 200, Los Angeles, California 90095 1772, USA
Biometrics 61:498-506. 2005..Simulation studies show that both ITS and SIAS outperform complete-case analysis with stepwise variable selection and that SIAS slightly outperforms ITS...
- Correlations of gene expression with blood lead levels in children with autism compared to typically developing controlsYingfang Tian
Department of Neurology, University of California at Davis, Sacramento, CA 95817, USA
Neurotox Res 19:1-13. 2011..We postulate that this may relate to the underlying genetic differences between the two groups, though other explanations cannot be excluded...
- Prevalence of viremia and oral shedding of rhesus rhadinovirus and retroperitoneal fibromatosis herpesvirus in large age-structured breeding groups of rhesus macaques (Macaca mulatta)Jessica A White
California National Primate Research Center, University of California, Davis, California, USA
Comp Med 59:383-90. 2009..Both RRV and RFHV are highly endemic in socially housed breeding colonies of rhesus macaques, and their patterns of infection are similar to that for the betaherpesvirus rhesus cytomegalovirus...
- Correlations between gene expression and mercury levels in blood of boys with and without autismBoryana Stamova
Department of Neurology, University of California at Davis Medical Center, Sacramento, CA 95817, USA
Neurotox Res 19:31-48. 2011..These findings might suggest different genetic transcriptional programs associated with mercury in AU compared to TD children...
- The relation of acculturation to overweight, obesity, pre-diabetes and diabetes among U.S. Mexican-American women and menLorena Garcia
Department of Public Health Sciences, University of California, Davis School of Medicine, 95616, USA
Ethn Dis 22:58-64. 2012..To estimate and compare the prevalences of overweight, obesity, pre-diabetes and diabetes among a nationally representative sample of Mexican-American, non-Latino white and black adults, and by acculturation for Mexican-Americans...
- Sustained reductions in drug use and depression symptoms from treatment for drug abuse in methamphetamine-dependent gay and bisexual menJames A Peck
UCLA Integrated Substance Abuse Programs, 11075 Santa Monica Boulevard, Suite 200, Los Angeles, CA 90025, USA
J Urban Health 82:i100-8. 2005..Findings show that behavioral methamphetamine abuse treatment yields reductions in methamphetamine use and concomitant depressive symptom ratings that are sustained to 1 year after treatment entry...
- Validation of a body condition scoring system in rhesus macaques (Macaca mulatta): assessment of body composition by using dual-energy X-ray absorptiometryLaura Summers
California National Primate Research Center, University of California, Davis, CA, USA
J Am Assoc Lab Anim Sci 51:88-93. 2012..0-to-5.0 BCS range. Absolute body fat in animals with BCS of 1.0 or 1.5 may be too low for accurate assessment by DEXA...
- Increased rate of amygdala growth in children aged 2 to 4 years with autism spectrum disorders: a longitudinal studyChristine Wu Nordahl
MIND Institute, University of California, Davis, School of Medicine, Sacramento, CA 95817, USA
Arch Gen Psychiatry 69:53-61. 2012..Precocious amygdala enlargement is commonly observed in young children with autism. However, the age at which abnormal amygdala enlargement begins and the relative growth trajectories of the amygdala and total brain remain unclear...
- Evolution of hemodialysis access resistance: a longitudinal 5-year model using functional principal components analysisAndrew I Chin
Department of Internal Medicine, Division of Nephrology, University of California, Davis School of Medicine, 4150 V Street, Suite 3500, Sacramento, CA, USA
Int J Artif Organs 32:864-71. 2009..To describe these changes, we applied a novel statistical methodology of functional principal component (FPC) analysis...
- Longitudinal patterns of viremia and oral shedding of rhesus rhadinovirus and retroperitoneal fibromatosis herpesviruses in age-structured captive breeding populations of rhesus Macaques (Macaca mulatta)Jessica A White
California National Primate Research Center, School of Medicine, University of California, Davis, California, Koelle Lab, University of Washington, Seattle, Washington, USA
Comp Med 61:60-70. 2011....
- A random-effects Markov transition model for Poisson-distributed repeated measures with non-ignorable missing valuesJinhui Li
UCLA Department of Statistics, PO Box 951554, Los Angeles, CA 90095 1554, USA
Stat Med 26:2519-32. 2007..The method is demonstrated using both simulated data sets and a practical data set from a smoking cessation clinical trial...
- Randomized placebo-controlled trial of baclofen for cocaine dependence: preliminary effects for individuals with chronic patterns of cocaine useSteven Shoptaw
UCLA Integrated Substance Abuse Program, Los Angeles, Calif 90025, USA
J Clin Psychiatry 64:1440-8. 2003..This screening trial evaluated whether the GABAB agonist baclofen demonstrated sufficient clinical efficacy to recommend an adequately powered trial of the medication as a pharmacotherapy for cocaine dependence...
- Participants receiving dehydroepiandrosterone during treatment for cocaine dependence show high rates of cocaine use in a placebo-controlled pilot studySteve Shoptaw
Friends Research Institute, Los Angeles, CA, USA
Exp Clin Psychopharmacol 12:126-35. 2004..No differences were detected between conditions for cocaine craving or adverse experiences. High levels of medication compliance were documented. Results argue against using high doses of DHEA as a pharmacotherapy for cocaine dependence...
- Randomized, placebo-controlled trial of baclofen and gabapentin for the treatment of methamphetamine dependenceKeith G Heinzerling
Integrated Substance Abuse Programs, Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA 90024, USA
Drug Alcohol Depend 85:177-84. 2006..To conduct a 16-week, randomized, placebo-controlled, double-blind trial of two GABAergic medications, baclofen (20 mg tid) and gabapentin (800 mg tid), for the treatment of methamphetamine dependence...
- Smoking cessation in methadone maintenanceSteve Shoptaw
Friends Research Institute, Los Angeles, CA, UCLA, Department of Psychiatry, Los Angeles, CA 90025, USA
Addiction 97:1317-28; discussion 1325. 2002..To evaluate relapse prevention (relapse prevention) and contingency management (contingency management) for optimizing smoking cessation outcomes using nicotine replacement therapy for methadone-maintained tobacco smokers...
- Transition Model for Incomplete Longitudinal Binary DataXiaowei Yang; Fiscal Year: 2003..In MLM approach, status of missingness is treated as a third category to extend the repeated measures into three-category ones. ..